Isolation of new surface active materials



United States Patent ()ffice 3,132,108 Patented May 5, 1964 fsolvingthe latter in an acid,

v propyl alcohol.

. wax oxidate solvent the column to ,elute 1 3,132,108 ISOLATION OF NEW SURFACE ACTIVE MATERIALS Demetrios Theodore Emmanuel Zalichi and Aleksander mGroszek, Sunbury-on-Thames, England, assignors to The BritishPetroleum Company Limited, London, England, a joint-stock corporation of Great Britain No Drawing. Filed Oct. 26, 1959, Ser. No. 848,509

Claims priority, application" Great Britain Oct. 31, 1958 7 Claims. 01. 252-356).

This invention rel-ates to the isolation and use of new j .surface active materials which are present in the oxidation products of petroleum waxes present in the heavy distillates and the residue from the vacuumdistilla-tion of crude petroleum. These Waxes are largelymicrocrystalline in structure and are often called microcrystalline Waxes or microwaxes, They are to be distinguished from the paraflin wax obtained from petroleum distillates which is largely macrocrystalline in structure.

Microwax oxidates are well-known materials which may be used for various purposes e.g. the preparation of polishes. The oxidates may be prepared by blowing finely dispersed air through microwaxes in the presence of a catalyst, e.g. manganese stearate or lithium stearate. The new surface active materials according to the invention are obtained by contacting a microwax oxidate with an adsorbent for surface active materials of the wax oxidate whereby the surface active materials are extracted j t-i-ve properties.

from'the wax oxidate by the adsorbent, separating the unextracted wax oxidate from the adsorbent, liberating the surface active materials from the adsorbent by disand recovering the liberated surface active materials from the solution of acid and adsorbent. V I The adsorbent may be washed with an organic solvent 1. for the oxidised wax after the adsorbent has been separated from the unex-tracted wax oxidate. solvents which may be used for this purpose petroleum ether,

Examples of are n-heptane,

The oxidised microwax; which is-to be contacted with the "adsorbent may be dissolved prior to the contacting step, in an-organic solvent for the oxidized microwax eig. n-heptane or petroleum ether.

1 The adsorbent is droxide,

preferably a basic metal oxide or hy- Particularly suitable adsorbents are magnesium oxide and'calcium hydroxide. -'Other suitable adsorbents are calcium oxide, barium oxide and barium hydroxide.

Particularly suitable acids for dissolving the adsorbent and liberating the surface active materials include hydrochloric acid and acetic acid.

According to one embodimentof the invention, the extraction of the surface active materials'is carried out in a chromatographic column containing the adsorbent, a solution of the oxidised wax feedstock in an organic solvent for the wax oxidate being fed to the column and .allowed to percolate through the adsorbent so that these wax is mixed intimately in the molten state with the adsorbent, which is then separated as in the previous embodiment and washed with a solvent for the wax oxidate.

benzene, acetone, chloroform and iso- Only a small proportion of the strongly adsorbed material can be removed by solvents for the mic-rowax oxidate, e.g. benzene, acetone, isopropyl. alcohol, chloroform and pyridine, and it is the unremoved portion of the strongly adsorbed material which has strong surface ac- The relative merits of using moltenwax'oxidate or a solution are that in the former case relativelylittle wash liquid is required'while in'the latter case high temperatures are unnecessary. e e

In all-three embodiments described, recovery of the surface active materials is achieved by dissolving the adsorbent containing them in an acid. The surface active materials are left floating on the surface of the solution of acid and adsorbent and they may be recovered by adding an organic solvent which is immiscible with the acid and dissolves them, e.g. n-heptane, petroleum ether or benzene, separating the two layers and recovering the surface active materails-from the organic solvent by distilling off the latter. The acid and organic solvent should, of course, be chosen so that two immiscible phases are formed. j The surface active materials produced according to the invention are resinous substances, which may harden and become brittle in time, and are darkin colour, usually reddish brown. They are soluble in many organic liquids including petroleum fractions. They consist mainly of long chainoxygenated material containing carboxyl and hydroxyl groups, some of which may be es-terified, also metal salts of organic acids. The yield of active material will depend on the oxidate itself and 'on' the manner in which the separation is carried out and is often in the range of 10 to 25% by weight.

By way of example, a surface active material was duction from a Middle Eastern vacuum residue of a 620/95 grade bright stock lubricating oil.) The oxidate was prepared by bubbling finely dispersed air, at a rate of 20 litres/hour/ 100 g. Wax, through. the residual wax at a temperature of 150 C., using 10%, by weight of the wax, of lithium stearate as oxidation catalyst. The oxidate had after 24 hours. The extractionwas carried out ina chromatographic column packed with 750 g. of magnesium-oxide and maintainedf'at a temperature of 120 E1503, offthe; wax

oxidate feedstock-were dissolved'in 100 cc. 'of-n-heptane and allowedtollpercolate down the 'columnfA further 4000 cc. of n-heptane were subsequently allowed-toper-- colate down the column to remove all but the most strongly adsorbed material.

The adsorbent was then removed from the columnv and dissolved in an excess of 50% acetic acid which caused the surface active material to be released.- They were recovered by agitating the acetic acid solution with 250 cc. n-heptane, separating the two liquid phases which. formed on settling and distilling off the n-h'eptane from the surface active material.

The surface active material recovered in thisv 'way had the following properties:

Molecular weight 22001-100.

Carbon content 74% wt. Hydrogen content 11.5% wt. Sulphur content 0.29% Wt. Hydroxyl groups 3.5% wt. Acid value 79 mg. KOH/ g.

a saponification number of 16 mg. KOH/g.

The ultra-violet spectrum gave no indication of the a g. of water. The resultant mixture was stirred rapidly presence of'any aromatic material. using a laboratory mixer operating at .3000 revolutions An indication of the surface activity of this material per minute. A stable water-in-oil emulsion was formed. is provided by the surface pressure or force exerted by This'emulsion was heated to 140 C. to drive off the a solution of the material in, n-heptane, as a thin film 5 water while high speed stirring was continued. The mix under compression. The following tableof results refers was then allowed to cool to atmospheric temperature to 0.1 mgpof the material. with gentle stirring. I Areasqcm: I 7 Pressure dyne/cm n examining the anhydrous dispersion of sodium 1400 O nitrite crystals so formed, under the microscope using a I 0 6 i polarised light, it was found that a fine even dispersion gg 0 9 of sodium nitrite crystals had been obtained, no individ- 4 0 ual crystal size being greater than S'IIIICIQI'ISQ 400 n 7.0 Where it IS. desired to form a dispersion of water- 300 105 soluble solids in a grease, a dispersion of the solid in a o 140 5 lubricating O11, prepared as described above, mayibe 100 95 mixed witha grease. 23 0 The additionof sodium nitrite to lubricants as a corrosion inhibitor using this emulsification technique is a An example of the activity of this surface active maknown but when using the emulsifying and dispersing terial is afforded by its ability to maintain carbon black 20 agents hitherto suggested for this technique, e.g. sodium in suspension in liquids. This was tested by suspending stearate, sodium hydroxy stearate, basic calcium alkyl 0.3 g. of carbon black,"8.8 microns, in 200 cc. of light sulphonates and sodium alkyl sulphonate, poor disper-" petroleum, and weighing the amount of carbon retained sions with large individual crystal sizes were obtained. in suspension at four'levels in cc. aliquots after 1 hour We claiin:' at 70 F. A commercial additive A was also tested, for 25 1. A process for isolating surface active materials from comparison. The results are tabulated below. a a a microwax oxidate, comprising, contaeting a liquid feed 7 stock containing a microwax oxidate with a basic acid- Material soluble adsorbent for the surface active materials con- Additive None mereial from Y tained in said oxidate whereby the surface active mate- Adcktive oxldised 30 1 microwax r1a.s are extracted from the said oxidate, said adsorbent being selected'from the group consisting of magnesium oxide, calcium oxide, barium oxide, calcium hydroxide Concentration, percent wt Nil 0.03 0. 03 I Carbon black retained in suspension, and barium hydroxide; contacting the unextracted wax top 8.2, 150 oxidate with an organic solvent selected from the group At level2 igg 25 consisting of n-heptane, petroleum ether, benzene, acefig 23 35552; a :9 tone, chloroform and isopropyl alcohol to separate said unextracted wax oxidate from the adsorbent with its con- Total 100 100 a 100 tents of adsorbed surface active materials, dissolving saidadsorbent in-an acid selected from the group consisting 111' another Similar test 8- of the carbonblack was 4.0 of hydrochloric and acetic acids to liberate the surface suspended in 10 of P a the visible settling active materialsfrom said adsorbent; recovering the surof carbon m was A Pmpanson i face active materials from the solution of acid and matqlal acFordmg the mventlfm Wlth a commerclal adsorbent by dissolving said liberatedsurface active maaddltlve B 15 shown In the followmg tableterials in an organic solvent selected from the group a l 45 consisting of n-heptane,lp'etroleum ether and benzene.

Height Ofsttled carbon h 2. The process as claimed in claim 1 wherein said feedstock comprises said microwax oxidate in a molten Time,mi11s- N0 ommercial ggi state and is intimately'mixed with said adsorbent, and additive Additive B, oxidised said adsorbent thereafter is separated from the resulting 1.0% Wt. niiglzvv atx; 5O mixture.

3. The process as claimed in claim 1 wherein said adsorbent is magnesium oxide.

4. 'The'process as claimed in claim 1 wherein said 'adsorbent is calcium hydroxide.

5. The process as claimed in claim 1 wherein said acid is hydrochloric acid.

6. The process as claimed in claim 1 wherein said acid is acetic acid. a a

i 7. The surface active material obtained by the process Thesurface active materials according to the invention. 6 set forth in claim l. 1 i are strong emulsifying and dispersing agents and an important use of them is in the emulsification of aqueous References Cited in the file of this patent solutions of inorganic salts in oleaginous liquids as an UNITED STATES PATENTS intermediate step inthe dispersion of water soluble mate- 2 479 339 Claussen et a1 May 17 1949 rials in oils. An example of this is as follows: 29057O4 Hirschler Sept 1959 2 g. of the surface active material described above p n were dissolved in g. of a /75 grade mineral lubri V OTHER REFERENCES eating oil. :To this solution was added slowly and with Schwartz et al.: Surface Active Agents, Interscience gentle stirring a solution of 15 g of sodium nitrite in 30 Publishers, Inc. (1949), pages 6, 17 and 19. 

1. A PROCESS FOR ISOLATING SURFACE ACTIVE MATERIALS FROM A MICROWAX OXIDATE, COMPRISING, CONTACTING A LIQUID FEEDSTOCK CONTAINING A MICROWAX OXIDATE WITH A BASIC ACIDSOLUBLE ADSORBENT FOR THE SURFACE ACTIVE MATERIALS CONTAINED IN SAID OXIDATE WHEREBY THE SURFACE ACTIVE MATERIALS ARE EXTRACTED FROM THE SAID OXIDATE, SAID ADSORBENT BEING SELECTED FROM THE GROUP CONSISTING OF MAGNESIUM OXIDE, CALCIUM OXIDE, BARIUM OXIDE, CALCIUM HYDROXIDE AND BARIUM HYDROXIDE; CONTACTING THE UNEXTRACTED WAX OXIDATE WITH AN ORGANIC SOLVENT SELECTED FROM THE GROUP CONSISTING OF N-HEPTANE, PETROLEUM ETHER, BENZENE, ACETONE, CHLOROFORM AND ISOPROPYL ALCOHOL TO SEPARATE SAID UNEXTRACTED WAX OXIDATE FROM THE ADSORBENT WITH ITS CONTENTS OF ADSORBED SURFACE ACTIVE MATERIALS, DISSOLVING SAID ADSORBENT IN AN ACID SELECTED FROM THE GROUP CONSISTING OF HYDROCHLORIC AND ACETIC ACIDS TO LIBERATE THE SURFACE ACTIVE MATERIALS FROM SAID ADSORBENT; RECOVERING THE SURFACE ACTIVE MATERIALS FROM THE SOLUTION OF ACID AND ADSORBENT BY DISSOLVING SAID LIBERATED SURFACE ACTIVE MATERIALS IN AN ORGANIC SOLVENT SELECTED FROM THE GROUP CONSISTING OF N-HEPTANE, PETROLEUM ETHER AND BENZENE. 